The present invention relates to an electromechanical actuator that includes a motion conversion mechanism, such as a screw mechanism, and converts a rotational drive force, which is output from an electric motor, to a linear drive force to output the linear drive force.
A conventional electromechanical actuator includes an electric motor and a screw mechanism and used in various fields, such as aircraft. Such an electromechanical actuator converts a rotational drive force, which is output from the electric motor, to a linear drive force by means of the screw mechanism and outputs the linear drive force. The electromechanical actuator moves an output portion in a straight line relative to a housing to drive a device. The electromechanical actuator is easily maintained compared to a hydraulic actuator, which is driven with the supply of hydraulic oil. This is the advantage of the electromechanical actuator.
U.S. Patent Application Publication No. 2007/0051847 describes an electromechanical actuator that includes a ball screw mechanism and two electric motors so that a rod linearly moves. Each electric motor is coupled to the ball screw mechanism. The ball screw mechanism converts rotation, which is output from the electric motors, to a linear movement of the rod (output portion).
U.S. Pat. No. 5,144,851 describes an electromechanical actuator that includes an electric motor, a planetary gear mechanism, and two ball screw mechanisms. One of the ball screw mechanisms surrounds the other ball screw mechanism. This structure allows an output of the electric motor to be selectively distributed to the ball screw mechanisms through the planetary gear mechanism. When the electric motor rotates one of the ball screw mechanisms, the rod (output portion) moves in an axial direction.
U.S. Pat. No. 4,637,272 describes an electromechanical actuator that includes a ball screw and ball nuts. Each ball nut can be rotated by an output of a corresponding electric motor. This allows the ball screw (output portion) to move in an axial direction when any one of the electric motors is driven.